1. Field of the Invention
This invention relates to valve systems of the type adapted to allow the introduction of a surgical instrument into a patient""s body. In particular, the invention is applicable to a cannula assembly wherein a cannula housing includes the valve assembly and the cannula is intended for insertion into a patient""s body to sealingly accommodate an instrument inserted through the cannula and valve.
2. Background of the Prior Art
In laparoscopic procedures surgery is performed in the interior of the abdomen through a small incision; in endoscopic procedures surgery is performed in any hollow viscus of the body through narrow tubes or cannula inserted through a small entrance incision in the skin. Laparoscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e. provisions must be made to ensure that gases do not enter or exit the body through the incision as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, laparoscopic and endoscopic procedures often require the surgeon to act on organs, tissues, and vessels far removed from the incision, thereby requiring that any instruments used in such procedures be relatively long and narrow.
For such procedures, the introduction of a tube into certain anatomical cavities such as the abdominal cavity is usually accomplished by use of a trocar assembly comprised of a cannula assembly and an obturator. The cannula assembly includes a cannula tube attached to a valve assembly which is adapted to maintain a seal across the opening of the cannula assembly. Since the cannula tube is in direct communication with the internal portion of the valve assembly, insertion of the cannula tube into an opening in the patient""s body so as to reach the inner abdominal cavity must maintain a relatively gas-tight interface between the abdominal cavity and the outside atmosphere.
Since surgical procedures in the abdominal cavity of the body require insufflating gases to raise the cavity wall away from vital organs, the procedure is usually initiated by use of a Verres needle through which a gas such as CO2 is introduced into the body cavity. Thereafter, the pointed obturator of the trocar assembly is inserted into the cannula assembly and used to puncture the abdominal cavity wall. The gas provides a slight pressure which raises the inner wall surface away from the vital organs thereby avoiding unnecessary contact with the organs by the instruments inserted into the cannula. Following removal of the obturator, laparoscopic or endoscopic surgical instruments may then be inserted through the cannula assembly to perform surgery within the abdominal cavity.
In view of the need to prevent leakage of the insufflation gas from the cavity, the cannula is typically provided with a valve assembly which permits introduction of surgical instruments to provide selective communication between the inner atmosphere of the cavity with the outside atmosphere. In this regard, there have been a number of attempts in the prior art to provide such a seal as part of the cannula assembly.
One form of cannula valve assembly includes a flapper valve which is pivotally mounted within the cannula assembly and is automatically opened by the obturator or other object when it is inserted into the proximal end of the cannula. Conventional flapper valves may also be manually opened by pivoting a lever on the exterior of the housing. See, e.g., U.S. Pat. No. 4,943,280 to Lander. Trumpet valves are also known.
Other conventional cannula valve devices for accommodating surgical instruments include a single or plurality of flexible sealing members as shown, for example, in U.S. Pat. No. 4,655,752 to Honkanen et al., U.S. Pat. No. 4,909,798 to Fleischhacker, U.S. Pat. No. 4,673,393 to Suzuki et al., U.S. Pat. No. 4,610,665 to Matsumoto et al., and U.S. Pat. No. 4,869,717 to Adair.
Further, typical hemostasis valve devices are shown, for example, in U.S. Pat. No. 5,041,095 to Littrell, and U.S. Pat. No. 5,000,745 to Guest et al., While attempts have been made to provide a valve assembly which maintains the integrity of the seal between the body cavity and the atmosphere outside the patient""s body. Seal systems provided to date have failed to address the full range of surgeons"" needs, especially when instruments varying in diameter are used. Specifically, sealing elements currently used may be damaged when an instrument, such as a pointed obturator is passed therethrough. Moreover, present seal systems have not provided adequate sealing about an instrument before and after an instrument is passed therethrough. Also, existing seal systems have failed to provide adequate sealing of a cannula, or a trocar assembly having a cannula which accommodates instruments of varying diameters. It is a further disadvantage of existing seal systems that adequate sealing is not provided in conjunction with a structure for holding a cannula in a desirable position in an incision with respect to a patient""s body.
It would therefore be desirable to provide a valve assembly which addresses these shortcomings in the art by maintaining a substantially fluid tight seal between an internal portion of a patient""s body and the outside atmosphere during insertion and manipulation of a surgical instrument into the patient""s body. Such an assembly may further provide stabilization or lateral limitation of motion of an instrument passed therethrough. Also, the valve assembly may inhibit fluids from exiting with the instrument while being withdrawn, and the valve assembly may inhibit contact with sealing structure. It is further desirable to provide a valve assembly for use with a cannula or trocar assembly which provides substantial fluid and gas tight sealing before and after an instrument is passed therethrough. It would also be desirable to provide a cannula which maintains a predetermined position of a cannula or trocar assembly in an incision.
The present invention provides a valve assembly which may be incorporated into a cannula assembly or utilized in combination with any type of tubular member for providing access into the body of a patient while permitting introduction of instruments through the valve assembly into the body. The valve assembly includes a sealing gasket which provides a desirable seal about an instrument inserted through the valve assembly. The valve assembly may further provide stabilization of the cannula or limit lateral motion of the cannula when an instrument is passed therethrough.
Also, the valve assembly may include more than one sealing element providing improved sealing qualities under varied conditions. At all times, the surgeon maintains control over the interface between the atmospheres within and without the patient""s body. Moreover, the present invention makes it possible to introduce instruments of varying sizes into the body and insures the maintenance of a gas seal despite instrument manipulation therethrough.
A valve assembly is provided for permitting the introduction of a surgical instrument into a patient""s body through a tube such as a cannula. The valve assembly includes at least one sealing gasket constructed of a flexible material and having a passageway. The passageway is substantially closed prior to insertion of an instrument through the valve assembly forming a substantial gas tight seal. When an instrument is inserted through the passageway of the valve assembly the flexible material defining the passageway resiliently engages an outer surface of the instrument in a substantially gas tight manner.
The sealing gasket may include sealing structure having first and second overlapping elements. The sealing gasket can be removably positioned on a frame or in a housing assembly such that the first and second overlapping elements are tensioned.
The valve assembly may further include sealing structure comprising a third element having a substantially central aperture. The third element may have a tapered portion and be constructed at least partially of a flexible material. The third element accommodates an instrument passed through its central aperture providing substantial sealing about the instrument passed therethrough. A retainer structure inhibits contact by the instrument with adjacent sealing structure such as, the first and second elements of the gasket assembly or the third element. The retainer structure includes at least one movable portion and a substantially central aperture for accommodating the instrument.
The valve assembly may further provide a sealing structure comprising a fourth element for substantially removing fluids from the surface of an instrument passed therethrough. The fourth element may include a substantially central aperture defined by a deformable material such that the central aperture is capable of accommodating the instrument.